Producer-gas boiler



W. B. CHAPMAN PRODUCER GAS BOILER July 30, 1929.

Filed July 29, 1926 2 Sheets-Sheet 1 D. be /M; M

ATTORNEYS '7 i INVENTOR 3 22 21 BY 6%,,

Z0 Z5 Z1 2 July 30, 1929. w. B. CHAPMAN PRODUCER GAS BOILER Filed July29, 1926 2 Sheets-Sheet 2 INVENTOR Ma. Q. CZ

I A ATTORNEYS Patented July 30, 1929.

PATENT OFFICE.

WILLIAM B. CHAPMALL OE JACKSON HE IGHTS, NEW YORK.

PRODUCER-GAS BOILER.

Application filed July 29,

The invention although applicable to boilers in general is especiallydesigned to enable the cheapest grade of fuel to be employed in boilersused for heating purposes, wherein the undue amount of smoke produced bythe cheaper grades of bituminous coal, and the tendency of this coal toburn irregularly with zones of high temperature which produce manyclinkers, heretofore have compelled the use of more expensive fuels,especially in small boilers.

The invention aims to enable the combustion of fuels to be carried onunder such conditions as will avoid the necessity of introducing air inquantities much in excess of those which are 'proper to completecombustion, avoid non-uniform conditions of combustion within the firebed, such as are caused by nonuniform fuel distribution, non-uniformdistribution of the blast over the difierentparts of the fire bed,non-uniform ash removal from different parts of the ash bed, blow holes,etc., to the end that the cheaper grades of bituminous coal may besatisfactorily employed.

According to the present invention the boiler is heated by means of adeep fire bed which generates producer gas, the firebed being severalfeet in thickness as contrasted to ordinary practiceof seldom more thanone foot, the fire bed being conditioned by means of an agitating memberwhich rotates around slowly in the bottom of the fire bed so as tospread the fuel out evenly over the fire bed and pack it against thewalls, eliminate blow holes,

grind up clinkers and eject the ash; this agitating member beingemployed in conjunction with a continuous fuel feed, preferably of theunderfeed type, whereby the fuel may be fed to the fire bed at theproper rate, the fire bed properly conditioned and the ash removed at arate corres onding to its rate of production, thus enab ing gas to beproduced which will be uniform asto quality and quantity. The gas thu 'sprodueed is then collected and mixed with secondary air and completelyburned within the boiler, the uniform production of gas as abovementioned making it possible to feed inthe proper amount of secondaryair which will be required to complete combustion.

1926. Serial No. 125,618.

F urthen objects and advantages of the in- VQIItlOIl w ll be in partobvious and in part spec fically pointed out in the descriptionhereinafter contained which taken in conjunction with the accompanyingdrawings','discloses a boiler adapted to operate in accordance with theinvention; such disclosure, however, should be considered merelyillustrative of its principles. In the drawings:

Fig. 1 is a central vertical sectional view of a boiler constructed inaccordance with the invention.

Fig. 1 is a detail view showing a device for automatically regulatingthe amount of secondary air.

Fig. 2 is a horizontal section taken on line 22 of Fig. 1.

Fig.- 3 is a horizontal section taken on line 3-.-3 of Fig. 1.

Fig. 4 is a. deta1l section taken on line 4-4 of Fig. 2.

Figs. 5 and '6 are diagrammatic views illustrating the shape of certainblades used to assist in feeding the fuel.

In the illustrated embodiment of the invention I have shown a boilerhaving inner and outer cylindrical shells 1 and 2' which enclose thechamber 3, which contains the fire bed, and also a secondary uppercombustion chamber or zone 4, the shells 1 and 2 being provided withupper domes 5 and 6 respectively th'ereby affording heating surfacesboth above and around the burning gases.

As shown the fire bed is supported upon a grate denoted generally bynumeral 7. lhe

' fire bed is conditioned by means of an agitating member 8 which isillustrated as extending substantially diametrically across the bottomof the fire bed and which rotates with regard to the fire bed. Theagitator is both up and out stroking in its action whereby the rotary.motion above mentioned causes an upward undulatory motion substantiallythroughout the fire bed, the agitator being shown as provided with anincllned forward surface 9 (Fig. 4) to facilitate its upstroking action.The outstroking action of the a itating beam tends to crowd outwardlyany arge clinkers which may form and the inner shell 1 of the boilerpreferably is provided with an annular wear ring 10 opposite the ends ofthe agitator, whereby clinkers may be ground up between the ends of theagitator and such wear ring. This wear ring 10 furthermore is providedwith inclined ridges 10 (Fig. 2) which prevent the firebed from turningaround bodily with the agitator. 4

In the illustrated form of the invention, the fuel is fed fromunderneath into the fire bed through a hollow column-11, passing upcentrally through grate 7 and fixedly connected to the agitating memberso as to turn the latter.' The hollow column 11 is shown as supportedand rotated by the ratchet gear 12 which in turn is rotatably supportedupon the hub 13 of a large gear 14 which latter runs on a ball-bearingraceway 15.

The fuel is fed in fromone or more spouts 16 which deliver it to a pan17 carried by the large gear 14 .and underlying the open lower end ofhollow'column 11. The pan 17 also fixedly supports a screw 18 which isenclosed by hollow column 11 and rotates relative thereto whereby fuelfed into the lower end of column 11 is raised through the column andinto the fire bed by this screw. The hollbw column 11 preferably isprovided with a spiral ledge 19 to assist inelevating the fueltherethrough.

Suitable devices are provided for crowding the fuel into the lower endof column 11 in position to be operated on by the screw. As shown thepan 17 carries a set of blades 20 having instroking curved inner ends 21thereon which tend to crowd the fuel into the openings 22 (Fig. 1) inthe bottom of column 11, and the lower end of column 11 carriesoppositely curved blades 23 which cooperate with the blades abovementioned to accenmate the crowding action upon the fuel and therebyassure that the latter is properly en gagedby the lower end of screw 18.

As shown-the pan 17 its blades 20 and screw 18 are rotated faster thancolumn 11 and an intermittent driving mechanism is provided for column11 which derives its motion from gear 14. In the' present embodiment, anengaging and releasing bar 24 is slidably car- 'ried by lugs 25 and 26on gear 14, the inner end of the bar engaging the ratchet teeth on gear12, and the outer end of the bar being provided with a lug 27 (Fig. 1)adapted to engage fixed cam members 28 to throw the bar 24 into and outof engagement with ratchet gear 12. Thus the cam members 28 may besuitably spaced around the periphery of gear 14 to cause the column 11to be driven through the medium of bar 24 during the desired fraction ofeach revolution of gear 14.

After being fed up into the fire bed through column 11 as abovedescribed the fuel tends to form a moundin the central zone of the firebed leaving the peripheral zone too shallow. The upper delivery end ofcolumn 11, or the central opening in the agitator, furthermore, ispreferably of restricted area as which is traveling downwardly to passout through the grate as ash. The outstroking action of the agitatingmember, however, which extends substantiallyto'the top of the fire bed,spreads the fuel out evenly over the fire bed and crowds it against thewalls thus preventing the air for combustion from passing up through anylocalized concentrated paths in the fire bed.

In operation gear 14 will be rotated at the speed necessary to feedfuelinto the fire bed at the .proper rate, and cam members 28 will be sospaced that the agitating member 8 is rotated intermittently at suchrate as may be necessary to maintain uniform conditions of gasproduction in the fire bed.

I also prefer to employ in connection with the agitating member a gratewhich is made adjustable in some suitable manner, so as to permit theeffective area of the grate openings as regards ash removal to bealtered without substantially affecting the flow of the air forcombustion upwardly through the grate. As shown the grate is made up oftwo relatively movable sections, the upper section 29 being fixed .andbeing provided with 'concentric series of arcuate grate openings 30which flare outwardly at their bottoms as shown in Fig. 1,,and lowergrate sections 31 are provided in the form of rings which respectivelyunderlie the series of grate openings 80. In the illustrated form of thein 'As the agitating member 8 revolves it grinds up the ash into sizessufficiently small to pass through openings 30 and the rate ofashdischarge thus will depend union the adjustment of lower gratesections 31. In this way by adjustment of the effective size of the ashopenings in the grate as regards ash removal, the operation of removingthe ash may be regulated to coordinate it properly with the operationsabove described with feeding the fuel and conditioning the fire bed. Theopenings 30, however, at all times are sufiiciently unobstructed topermit the air for combustion to flow upwardly therethrough.

In the illustrated form of the invention ash drops down from the grateon to a rotary table 85 carried by hollow column'll, the ash beingconfined to the table by an annular wall 36 until it is carried aroundagainst a fixed sweep 37 which pushes it into a watersealed chamber 38from which the ash may be removed in any suitable manner.

Since the space in the neighborhood in the axis of rotation of theagitatingmember through which water-cooling connections to the lattermost feasibly can be made, is preempted by the fuel feeding mechanism, Iprefer to cool the agitator by causing wet ash to travelover-its face.As shown the upper grate section 29 is provided'with a series of annulartroughs 39 which are in communication with each-other through the gaps40 between grate openings 30, and have suitable water inlet and outletconnections 41 and 42 (Fig. 1) leading thereto whereby the'ash withinthe troughs is constantly saturated with water. The agitating member 8furthermore is provided with tongues 43 (Figs. 1 and 4) which extenddown into the troughs 39 and thus cause the wet ash to pass upward lyover the inclined forward surfaces 9 of the agitator arms and over itstop. As shown the agitating member is open on the underside and alsoprovided with openings 44 (Figs. 1 and'4) in the rear walls of its armswhereby a portion of the air for combustion may pass through theseopenings up through the hollow beam and out thus assisting in coolingthe'agitator.

In the operation of the apparatus thus far described the fuel will befed in, spread out evenly over the fire bed, the fire bed agitated topromote uniform conditions of combustion therein, and the ash ground upand discharged, all in proper coordination to conform to the rate offuel consumption, the fire" bed being maintained at substantiallyuniform depth whereby the producer gas generated will be substantiallyconstant as regards quality and quantity. The hot producer gas is thencollected and mixed with secondary air in a restricted. throat topromote uniformity in the mixture. As shown, a refractory arch 45overlies chamber 3 and is provided with a central opening or mixingthroat 46 through which the hot producer gas collected under said archpasses'from chamber 3 intd chamber 4 and is properly mixed withsecondary air from a suitable number of air feed passageways 47 leadingtangentially into the opening 46 through arch 45. It will beunderstoodthat one or more of these mixing throats or openings 47 may be employed,accordin to the size of the a paratus. This metho of introducin the airboth preheats the air and prevents t e arch 45 from becoming overheated.It also produces a whirl which aids in the proper mixing of the air andgas. The fact that the quality and quantity throat 46 may be maintainedsubstantially uniform as above described, makes it possible .to socontrol the amountlof secondary air fed in so that approximately theexact amount of air to complete the combustion of the producer gas willbe supplied. As shown disks 48 hav- 1ng different sized openings 49therein, overlie the inlet ends of the air passageways 47,

whereby the amount of' air fed in may be ad- I ing gases pass upwardlythrough throat 46 to the top of combustion chamber 4 and then turn topass downwardly through an annular series of fire tubes 50 to an annulargathering chamber 51 at the bottom of the boiler heating surfaces, fromwhence the spent gases may be led off through a suitable exhaust flue 52SlFig: 2).

T e re bed may be operated either by air under pressure suppliedundereneath the grate and through the secondary air feed passageways 47or by suction through the exhaust flue 52 in the latter event nopressure for the secondary air feed passageways will be required as thesuction will automatically draw in the required amount of secondary airthrough these passageways as well as draw the primary air up t rough thefire bed.

Preferably. the heating surfaces of the boiler enclose the fire bed, asshown, thus im-' proving the efficienc of the heatinterchange as well askeeping t 1e enclosing walls of the fire bed sufiiciently cool toprevent the undue building up of slag or solidified clinkers thereon.

, A boiler of the above type may be operated with the cheapest grades ofbituminous coal without producing undue amounts of smoke and dust sincethe fuel, being fed in from underneath does not cause fineun'consumedcoal particles to pass off with the gases of combustion, and theagitation of the fire bed maintains uniform conditions of gas productionsuch that the proper amounts of secondary air may be fed in to completecom bustion. If-the fuelbed were non-uniform in thickness at differenttimes, or in different zones thereof, or non-uniform as regards pasthroat 46, and thus the features of the uniform fuel feed anddistribution, uniform fire bed agitation and ash removal are all vitalin enabling the boiler to operate successfully.

While a specific apparatus has been described for carrying out theinvention, it will be obvious that the invention is applicable to otherforms of boilers than the one shown and that many changes may be madetherein without departing from the principles of the invention as setforth in the appended claims.

I claim: I

1. A boiler having heat exchange surfaces disposed contiguous to acombustion cham; ber, means for feeding fuel up from underneath into afuel bed located in the lower portion of said chamber, means forinsuring-the formation of producer gas of substantially uniform qualityin said firebed, and-means for supplying secondary air within saidchamber to the producer gas so formed, to burn the latter in saidchamber.

2. The method of heating boilers which I comprises feedingj fuel up fromunderneath into a chamber having heat exchange surfaces disposedcontiguous thereto, maintaining substantially uniform producer gasmaking conditions in the fuel bed thus formed in the lower part of saidchamber, admitting air to the fuel bed and thereby forming pro ducer gasof substantially uniform quality and mixing secondary air with saidproducer gas in said chamber to complete the combustion thereof. v

3. A boiler having heat exchange surfaces disposed contiguous to acombustion chamber, means for feeding fuel u from underneath into a fuelbed located in t e lower portion of said chamber, means for insuring theformation of producer gas of substantially uniform quality in saidfirebed, comprising an upstroking agitating member working in the bottomportion of the firebed, and adapted to cause a vertical undulatingmovement therein, and means for supplying secondary air within saidchamber to the producer gas so formed to burn the latter in saidchamber.

4. A boiler having heat exchange'surfaces disposed contiguous to acombustion chamber, a grate beneath said chamber adapted to support afirebed, means for feeding fuel upwardly through the central part ofsaid grate, means for insuring the formation of producer gas ofsubstantially uniform quality in said firebed, comprising an upstrokingagitating member disposed over said grate and adapted to cause avertical undulating movement in the firebed and means for supplyingsecondary air within said chamber to the producer gas so formed to burnthe latter in said chamber.

5. The method of heating boilers which comprises uniformly feeding fuelup from underneath into a chamber having heat exchange surfacescontiguous thereto, producing a vertical undulating movement in thefirebed and uniformly withdrawing ash comprises feeding fuel up fromunderneath into the central portion of a chamber having heat exchangesurfaces contiguous thereto, to the top portion of a firebed located insaid chamber, agitating the lower part of the firebed to produce avertical undulating motion therein, withdrawing ash from the lowerportion of the firebed to cause partially consumed fuel to travelgradually downward around the central upwardly traveling fresh fuel allto form producer gas of substantially uniform quality and'mixingsecondary air with said producer gas in said chamber to complete thecombustion thereof.

7. A boiler comprising heat exchange surfaces and a combustion chamberdisposed symmetrically about a common vertical axis, means for feedingfuel up from underneath into the lower portion of said chamber, saidmeans feeding the fuel symmetrically with regard to said axis, a rotaryagitating member sweeping through substantially the entire lower portionof said chamber and also turning substantially about the aforesaidcommon axis, means also act-ing substantially symmetrically with regardto said axis for supplying secondary air to said chamber.

8. A boiler comprising heat exchange surfaces and a combustion chamber,both disposed substantially symmetrically about a common vertical axis,said chamber having at it bottom, cylindrical firebed enclosing wallsand a rotary fire bed agitating member sweeping substantially the entirecross sectional area within said firebedenclosing walls and turningabout said axis, means acting substantially symmetrically with regard tosaid axis for supplying secondary air to said chamber, and for feedingfuel upwardly into the firebed. I

9. A boiler having heat exchange surfaces disposed contiguous to acombustion chamber, means for feeding fuel into a firebed located in thelower portion of said cham ber, means for insuring the formation ofproducer gas of substantially uniform quality 1n said firebed, and apartition divlding said chamber into a; lower producer gas gathermgchamber and an upper burning chamher, said partition having a centralopening therethrough and means associated with said opening forunixingsecondary. air with producer gas rising through the opening, saidchamber having exit passageways periph erally disposed With regard tosaid central opening.

10. A boiler comprising heat exchange surfaces and a combustion chamberdisposed stantially the entire lower portion of said symmetrically abouta common vertical axis, chamber and also turning substantially means forfeeding fuel up from underneath about the aforesaid common axis. 10 7into the lower portion of said chamber, said In testimony that I claimthe foregoing, I 5 means feeding the fuel symmetrically with havehereunto set my hand this 24 day of regard to said axis, a rotary up andoutstrok- July, 1926.

ing agitating member sweeping through sub- WILLIAM B. CHAPMAN.

CERTIFICATE OF CORRECTION.

Patent No. 1,722,495. Granted July 30, 1929, to

-WILLIAM B. CHAPMAN.

It is hereby certified that error appears in the printedspecification ofthe above numbered patent requiring correction as follows: Page 4, line65, claim 5, after the word "'firebed" insert the words "to level thefuel out over the chamber", lines 66 and 67, strikecout the words "tolevel the'fuel out over the chamber"; and that the said Letters Patentshould be read with these corrections therein that the same may conformto the record of the case in the Patent Office.

Signed and sealed this 1st day of October, A. D. 1929.

' M. J. Moore, (Seal) Acting Commissioner of Patents.

